J. Phys. I France 1 (1991) 1019-1028
The thermoactivation rate of charged particles in a magnetic fieldD. A. Garanin
Moscow Institute of Radio Engineering, Electronics and Automation, 117454, Moscow, Prospect Vernadskogo 78, U.S.S.R.
(Received 19 November 1990, revised 5 March 1991, accepted 11 March 1991)
We consider a diffusion of a charged particle over a three-dimensional barrier in a magnetic field. By the solution of the Fokker-Planck equation it is shown that the magnetic field causes the diminishing of the pre-factor in the expression for the particle's thermoactivation rate: , . Unlike the two-dimensional case considered earlier [3, 4], in the general situation this diminishing is non-uniform with respect to the orientation of the vector B, with a saturation at some non-zero level for some range of orientations. The latter causes the splitting of the relaxation peak in the bulk materials containing randomly oriented two-well relaxators at high magnetic fields.
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